Many processes for semiconductor and disk manufacturing require extremely clean workpieces before the processes may start. For example, particulates or contaminates that attach to or form on the workpiece before processing may eventually cause defects in the workpiece. When the workpieces are disks to be processed, such particulates or contaminates may be hydrophobic or hydrophilic, and may include layers: e.g., thin oxide surface layers; surface asperities such as scratches, nodules, and ridges that may be induced by a prior polishing operation; materials adhered to the workpiece due to the polishing operation; and loosely adhered particles from the environment in which the workpiece has been stored. These particulates or contaminates may also be aged, and thus be more stable and more difficult to remove before the processing. Cleaning, then, is a process intended to remove substantially all of such particulates or contaminates from workpieces before processing, such as processing of magnetic media or semiconductor workpieces. A clean workpiece is thus a workpiece from which substantially all of such particulates or contaminates have been removed before processing.
Therefore, there is a need for improving techniques for cleaning workpieces, such as those workpieces that present problems and require removal of substantially all of such particulates or contaminates from the workpieces before processing. Moreover, these improved techniques must allow cleaning of a workpiece to be done quickly so as to reduce the cost of capital equipment for the cleaning.
What is needed then, is apparatus configured to clean workpieces quickly, yet during the cleaning operation of one workpiece, to increase the time provided for contact at the brush-workpiece interface according to characteristics of the workpiece. What is also needed is apparatus configured to clean a group of workpieces, wherein all workpieces of the group are cleaned by the same apparatus, e.g., by the same brush.